What does "in-season vegetables" mean? A guide to the timing of in-season vegetables now

In the past, vegetables were only produced within limited time periods, but now with new technology we can see any vegetable all year round; however, today's vegetables are not as nutritious as before.
Every fruit and vegetable has a season best suited to its growth, called "in-season fruit and vegetables." With the improvement of fruit and vegetable varieties and advances in agricultural technology, growing out-of-season fruit and vegetables is no longer difficult; in other words, almost any fruit or vegetable you want to eat can be enjoyed all year round. However, because out-of-season fruit and vegetables have weaker constitutions when grown in unsuitable seasons, they require more pesticide protection, and they are more expensive than in-season produce, so when choosing fruit and vegetables, in-season ones are still the best.